1. Technical Field
An aspect of the invention relates to an electro-optical device or a projector.
2. Related Art
A projection display, such as a projector, mainly include a light source; a light valve that modulates light emitted from the light source; and a projection lens that projects light modulated by the light valve onto a screen or the like. A liquid-crystal device is often used as the light valve that modulates light.
The liquid-crystal device used as the light valve has a structure in which a pair of substrates holds a liquid-crystal material therebetween. Such a liquid-crystal device is required to have high efficiency for light utilization in order to allow light from a light source to contribute to display as much as possible. For example; JP-A-2000-330101 discloses a technique for forming microlenses on a pair of substrates as a method for enhancing efficiency for light utilization. In this technique, the formation of the microlenses on each of the substrates enhances the effect of collecting light into pixel regions, thereby increasing efficiency for light utilization.
On the other hand, there are problems as follows: difficulty in alignment for adjusting the foci of the microlenses, the occurrence of loss (Fresnel loss) due to the passage of light through the plurality of microlenses, an increase in cost due to the formation of the microlenses on each substrate, and the like.
In contrast, it is known that a technique in which by bonding a prismatic substrate onto the outer side of one substrate of the pair of substrates, the prismatic substrate including prismatic elements which are each in the form of a groove and which are disposed in interpixel regions, reflecting light coming through the one substrate is reflected from the grooves of the prismatic elements into the pixel regions. This technique can collect light into the pixel regions and improve efficiency for light utilization without the occurrence of the above-described problems.
In the liquid-crystal device, the pixel regions are arrayed in a matrix. The interpixel regions include leads, active elements, and the like. Irradiation of the leads and the active elements with light causes electrical failures. Thus, the interpixel regions are usually covered with light-shielding portions. In the prismatic substrate, the opposite substrate is generally bonded on a surface in which the prismatic elements are disposed. Each of the light-shielding portions is disposed on the opposite substrate so as to overlap a corresponding one of the prismatic elements when viewed in plan.
However, in the case where the prismatic elements are disposed on the substrate, the prismatic elements are remote from the light-shielding portions by the thickness of the opposite substrate. Thus, light rays traveling obliquely to the normal to the substrate through the pixel regions, which are located between the prismatic elements, and light rays reflected from the prismatic elements and then coming through the pixel regions are partially absorbed by the light-shielding portions, in some cases. These light rays are light rays originally designed to be emitted from the liquid-crystal device and to contribute to display. Thus, efficiency for light utilization is reduced because of absorption of light. Other electro-optical devices also have this problem as well as the liquid-crystal device.